SAN DIEGO -- San Diego Gas & Electric officials are advising customers Wednesday to inspect their furnaces and perform any needed maintenance to help ensure safe and efficient operation as colder weather approaches.

With home energy bills projected to be 20 to 30 percent higher than last winter due to natural gas costs, SDG&E officials said ensuring appliances are operating efficiently can help keep heating expenses down.

Failure to perform annual maintenance on gas appliances can also result in exposure to carbon monoxide, which can cause nausea, drowsiness, flu-like symptoms and even death, company officials said.

"Now is the time to perform maintenance on home-heating appliances to ensure safe operation," SDG&E's Michelle Mueller said. "If customers think their heating appliances are not functioning properly, they should call a licensed heating contractor or plumber or SDG&E."

SDG&E recommended residents:

Not store items in, on or around the appliance.
Have gas furnaces checked at least once a year by a licensed heating contractor, plumber or SDG&E.
Vacuum and clean regularly around the furnace, particularly around the burner compartment, to prevent a build-up of dust and lint.
Check their forced-air furnace's filter monthly for lint buildup.
Reinstall the front panel door of the furnace properly and never operate it without the panel in place.
Check the appearance of the flame. If the flame is yellow, large and unsteady, the furnace needs to be inspected immediately.

For more information, click on www.sdge.com.